class_docstr: 构建词汇表,增加词汇，删除低频词汇
docstr: 添加初始tokens
docstr_tok: ["\u6dfb\u52a0\u521d\u59cbtokens"]
code: def _add_init_tokens(self):
      """
      添加初始tokens
      """
      for token in self.init_tokens.values():
          self._add_word(token)
  
file_path: DeepKE/src/deepke/relation_extraction/standard/tools/vocab.py
imports: import logging
  from collections import OrderedDict
  from typing import Sequence, Optional
label_desc: Use image node_id 2 for calling the Vocab obj's underlying member method code with example usage: obj._add_init_tokens() without return types